PCR, Polymerase chain reaction—Mullis invented PCR, the process for amplifying nucleic acids, in 1993 while at Cetus Corporation. PCR has revolutionized the fields of microbiology, medical diagnostics, and forensics. PCR allows scientists to identify a fragment of DNA genetic code and then reproduce it infinitely. It is used to discover faulty genes in hereditary diseases and diagnose viral and bacterial infections, including HIV. Police can get decisive information from a single drop of blood or a hair. Other uses include determining genetic ties and evolutionary connections between animal species including extinct animals whose remains are fossilized. It was used to identify the remains of Russia's last czar, Nicolas II. (1998)